Learn Croatian: Jesi li rekao da je u kući dim? - Did you say that there is smoke in the house?

Reći is an irregular verb ending in -ći. In the past tense, its stem changes rather than following the standard rules. For a masculine subject ('you' in this sentence), it becomes rekao. If you were asking a woman, it would be rekla.

Why does the sentence start with jesi li?

To ask a yes/no question in the past tense, Croatian uses the helper verb biti (to be) plus the question particle li. Jesi is the 'you' form of biti. Together with the past verb rekao, jesi li rekao means 'did you say'.

Why does the word for house change to kući in this sentence?

The preposition u meaning 'in' or 'inside' requires the locative case when describing a fixed location. The noun kuća drops its final -a and adds -i to become kući (in the house).

The English translation says 'there is smoke', but where is the Croatian word for 'there'?

Croatian doesn't use placeholder words like 'there' in these phrases. To say 'there is smoke', you simply use the verb 'to be' (je) and the subject (dim). Literally, the second half of the sentence just translates to 'that is in the house smoke'.